Computer simulation of real-world environments is one of the major challenges of computer graphics. The ultimate goal is to capture a digital representation of a real-world environment, which later can provide observers with a realistic visual experience of interactively moving or “walking” through the environment. Thus, so-called “interactive walkthroughs” are types of computer graphics applications, where an observer moves within a virtual environment.
Applications for this technology include, but are not limited to, remote education, virtual heritage, specialist training, electronic commerce, and entertainment. For instance, students can “visit” famous historical sites they are studying in school (e.g., museums, temples, battlefields, and distant cities), archeologists can capture excavation sites as they evolve over time, soldiers and fire fighters can train in simulated environments, real estate agents can show potential buyers the interiors of homes for sale via the Internet, and people around the world can enjoy virtual travel and multi-player three-dimensional (3D) games.
The major research challenge in such applications is to develop effective techniques for capturing, representing, and rendering large environments with photorealistic imagery from arbitrary viewpoints at interactive rates.
Current computer graphics techniques fall short of meeting these challenges. Although geometry-based walkthrough systems have been demonstrated for large-scale environments, the images they produce are far from photorealistic. Alternatively, image-based rendering (IBR) systems produce photorealistic images by resampling photographs, but usually work only for small and/or diffusely illuminated environments as seen from a limited range of viewpoints. Similarly, most computer vision algorithms that extract three-dimensional models from images have difficulties with scenes containing complex occlusions and specular surfaces.
Thus, there exists a need for techniques that overcome the above-mentioned drawbacks by providing photorealistic walkthroughs of large spaces rendered from arbitrary viewpoints at interactive rates.